Synchronizing alternating-current machines.



No. 678,|78. Patented July 9, IQOL E. m. HEWLETT.

SYNCHRONIZING ALTERNATING CURRENT MACHINES.

(Application filed July 28, 1899.) (No lludel.) 2 Sheets-Sheet L Fig.1.

Inventor.

Edward I'Tl. Hewlett W 02 Wntnesses TNE "cams PETERS co. PHGTO-LIYHQ" WASMINGTCN. n. cy

No. 678,08. Patented July 9, l90l. E. M. HEWLETT. SYNCHRONZING ALTERNATING QURRENT MACHINES.

(Application filed July 28, 1899;

2 sheets-sheet 2.

(No Model.

lnve ntor Edward m. Hewlett I Witnesses.

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UNITE STATE PATENT EDWARD M. HEWLETT, 0E SCHENECTADY, NEW YORK, ASSIGNOR TO THE GENERAL ELEoTRIo COMPANY, OF NEW YORK.

SYNCHRONIZING-ALTERNATlNG-CURRENT MACHINES.

SPECIFICATION forming part of Letters Patent N 0. 678,178, dated July 9, 1901. Application filed July 28, 1899. fierial No. 725,345. (No model.)

To all whom it may concern:

Be it known that I, EDWARD M. HEWLETT, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New Y0rk,have invented certain new and use ful Improvements in Synchronizing Alternat ing-Ourrent Machines, (Case No.' 1,119,) of which the following is a specification.

This invention relates to means for coup-,

ling alternating-current dynamo-electric machines in parallel in a distribution-circuit.

In carrying outmy invention I provide a controlling-switch arranged to have its ter-' cially in the case-where a lamp constitutes such indicator, the employment of a filament of higher resistance and one which responds more sensitively to the separated phases and permits a sharper indication when the ma chines are in synchronism.. The features of novelty will be more fully described hereinafter and will be particu larly indicated in the claims. In the accompanyingdrawings, which illustrate the invention, Figure 1 is a diagram of the circuit connections of an organization embodying my improvements. Fig. 2 is a sectional view of the controllingswitoh.

Referring first to Fig. 1, 1 2 3 represent a plurality of alternating-current generators adapted for connection with a pair of distributing bus-bars 4-. 4:. The connections are controlled by a hand-operated switch 5 67, adapted to simultaneously close the generator-terminals on both bus-bars. Each switch is connected to an auxiliary circuit-breaker S 9 10, which opens a connection of one pole of the generator with the bus b'ar of unlike instantaneous sign when the generator is connected to the bus-bars and closes said connection when the generator is disconnected from the bus-bars. Running through the switchboard is an auxiliary bus-bar 4: con nected with one terminal of a phase-indictor,

whichin the example shown in the drawings is a transformer, one primary terminal of which is connected to the auxiliary bus-bar and the secondary of which feeds a high-resistance incandescent lamp 11. By phaseindicator herein I am who understood as including any device which'gives an intelligible indication of visual, oral, or other characterof an approach'or recession from identity of phase relation of two alternating currents. The other terminal of the transformer primary connects with the bus-bar 4.

The mechanical construction of the switch will be more fullynnderstood' upon an examination of Fig.2, which shows its arrange ment with relation to a switchboard, the

i switch being shown in full linesin closed position with relation to the distributing busbars and in dotted lines in open relation thereto. The controlling-handle is'connected to a blade pivoted upon a stud 12, mounted in the switchboard and which on the rear side is connected to one of the generator-terminals." Theupper end of the blade may be :forced into'or against an elastic clip mounted upon a stud in the switchboard, which forms a terminal'for a fixed connection with one of the bus-bars. A link 13, pivoted to the switch-blade at a pointbetween the handle and its journal, pivot-ally connects with the circuit breaker 8, journaled on a bracket mounted on the rear of the switchboard. The free end of the circuit-breaker is adapted to enter or engage a spring-clip 14. WVith this organization when the switches are closed in the position shown with respect to machines 1 and 3 they are coupled in parallel relation to the distributing bus-bars; but when open, as shown with relation to machine 2, its terminal connections with the distributing bus-bars are reversed by means of the circuit-closing action of the blade 9. The circuit of the phase-indicator, however, is controlled by a branch from an auxiliary bus-bar 4 a leg of which extends adjacent to each machine and is provided with sockets to receive a U-shaped switch-plug, which when inserted, as shown in connection with machine 2 at 15, throws the phaseindicator into circuit, and by reason of the reversed position of the machine-terminals on open circuit with relation to the bus-bars the phaseindicator is in circuit with two machines in series, and therefore has a double potential. This results in an advantage in practice in permitting a higher resistance and finer filament to be employed in the lamp which gives the phase indication, thereby making it quickly responsive to the changes of current under varied displacements of phasebetween the bus-bars and the machine being synchronized.

It will further be evident that with the switch construction employed by me when the machine is thrown upon the circuit the circuit of the phase-indieator is simultaneously broken, thereby preventing any shortcircuiting tendency or any injury to the indicator, and since this is done by the action of the switch which connects the machine to the bus-bars there is no opportunity for mistakes.

The circuit through the phase-indicator may be traced as follows in the position shown in the diagram: from the right terminal of generator 2 to the switch-plug 15, thence through the primary of the transformer or the terminal of the phase-indicator to the bus-bar 4, a branch continuing to the right side of each machine 1 and 3, thence through the machines 1 and 3 to bus-bar t, thence to the connection 16 with the circuitbreaker 9, and through afnse 17 to the circuitbreaker, which is now closed, to the left brush of generator 2. Thus in case of failure to open the synchroniZing-circuit the fuse will blow and cut out the machine 2.

It will thus be seen that the potential of two machines is upon the phase-indicator, thereby increasing its effectiveness. As the machines approach synchronism the luminosity of the lamp pulsates, and when at its maximum brillianey the two machines are identical in phase and the coupling-switch may be thrown. Simultaneously therewith the circuit of the phase-indicator is opened by the action of the circuit-breaker 9.

What I claim as new, and desire to secure by Letters Patent of the United States, is

1. Meansforsynchronizingalternating-current dynamo-electric machines, comprising a phase-indicator, means for connecting it in series relation to the machines being coupled, a switch for closing the circuit between the machines when in step, and a circuit-breaker controlled by the same agency as the switch for simultaneously opening the circuit of the phase-indicator.

2. Means for coupling alternating-current dynamoelectric machines in parallel, comprising a phase-indicator, means for coupling it in circuit with two machines to be connected, and a circuit-breaker operated simultaneously with the switch which throws the machine on-the distrihuting-terminals, said circuit-breaker being adapted to open the indicator-circuit.

3. Means for coupling alternating-current machines in parallel relation, comprising a phase-indicator in series relation to the two machines being coupled, a switch for connecting each machine with like or unlike terminals to the terminals of the distributioncircuit when .in closed or open position re spectively, and means for closing a circuit through the phase-indicator in the open position of the switch operated by the same controlling-handle.

4. Means for coupling alternating-current machines in parallel relation to an alternating-current distribution-circuit, comprising a switch for connecting one of the several machines in parallel relation to distributing-ten minals in its closed position, auxiliary con tacts controlled by said switch in its open position, a transformer having its primary circuit governed by said contacts, means for connecting the machines in series relation when said contacts are closed, and a high-resistance incandescent lamp in the secondary circuit of the transformer.

5. Means for coupling a plurality of alterhating-current machines in parallel relation to an alternating-current distribution-circuit, comprising a controlling-switch governed by a single handle, two sets of switch-contacts, one controlling connection with the distribution-circuit, the other with a phase-indicator in series relation to two machines, the contacts being governed by the alternate posi* tions of the switch, and an auxiliary circuit breaker in the phase-indicator circuit.

6. Means for connecting alternating-cur rent machines in parallel comprising a trans formerhavingin its secondary circuitaphasoindicator, switch mechanism for coupling two machines to be synchronized in series relation on its primary or in parallel relation to a distribution-circuit, and an operating-ham dle for shifting the switch mechanism.

In witness whereof I have hereunto set my hand this 26th day of July, 1899.

EDlVARD M. HEWLETT.

Witnesses:

BENJAMIN B. HULL, ALEXANDER D. LUNT.

IIO 

